#include <bits/stdc++.h>

using namespace std;

ifstream fin ("darb.in");
ofstream fin ("darb.out");

vector<int>v[100002];
int n, x, y, d[100002], viz[100002], maxx, p;

void dfs(int x) {
  viz[x] = 1;
  for (int i = 0; i < v[x].size(); i++) {
    int vecin = v[x][i];
    if (!viz[vecin]) {
      d[vecin] = d[x] + 1;
      if (maxx < d[vecin]) {
        p = vecin;
        maxx = d[vecin];
      }
      dfs(vecin);
    }
  }
}

int main()
{
  fin >> n;
  for (int i = 1; i < n; i++) {
    fin >> x >> y;
    v[x].push_back(y);
    v[y].push_back(x);
  }
  d[1] = 1;
  dfs(1);
  memset(viz, 0, sizeof(viz));
  memset(d, 0, sizeof(d));
  d[p] = 1;
  dfs(p);
  maxx = 0;
  for (int i = 1; i <= n; i++) {
    if (maxx < d[i])
      maxx = d[i];
  }
  fout << maxx;
  return 0;
}